There are several different methods of producing electronic reflective and transmissive displays. The most well known and widely used method is to use liquid crystal molecules as the electro-optic material. In the liquid crystal family, a vast range of molecules could potentially be used to create the electro-optic modulated material. Some of these liquid crystal molecules include, twisted nematic, cholesteric-nematic, dichroic dye (or guest-host), dynamic scattering mode, and polymer dispersed to name a few. Most of these liquid crystal molecules require other films, such as, alignment layers, polarizers, and reflective films.
Another type of reflective display composing an electro-optic material is an electrophoretic display. Early work such as that described in U.S. Pat. No. 3,767,392, “Electrophoretic Light Image Reproduction Process”, used a suspension of small charged particles in a liquid solution. The suspension is sandwiched between two glass plates with electrodes on the glass plates. If the particles have the same density as the liquid solution then they are not affected by gravity, therefore the only way to move the particles is using an electric field. By applying a potential to the electrodes, the charged particles are forced to move in the suspension to one of the contacts. The opposite charge moves the particles to the other contact. Once the particles are moved to one of the contacts, they reside at that point until they are moved by another electric field, therefore the particles are bistable. The electrophoretic suspension is designed such that the particles are a different color than the liquid solution. Therefore, moving the particles from one surface to the other changes the color of the display. One potential problem with this display is the agglomeration of the small charged particles when the display is erased, i.e., as the pixel is erased, the particles are removed from the contact in groups rather than individually. Microencapsulating the electrophoretic suspension in small spheres solves this problem, as shown in U.S. Pat. No. 5,961,804, “Microencapsulated Electrophoretic Display.” FIG. 1 shows the typical operation of a microencapsulated electrophoretic display. In this display the particles are positively charged and are attracted to the negative terminal of the display. The charged particles are white and the liquid solution they are suspended in is dark, therefore contrast in the display is optionally achieved by selectively moving some of the particles from one contact to the other. In this type of display, the electro-optic material 37 is the electrophoretic material and any casing used to contain the electrophoretic material.
A similar type of electro-optic display, a twisting ball display or Gyricon display, is described in U.S. Pat. No. 4,126,854, “Twisting Ball Display.” It was initially called a twisting ball display because it is composed of small spheres, one side coated black, the other white, sandwiched between two electroded 5 glass plates. Upon applying an electric field, the spheres with a positive charged white half and relative negative charged black half are optionally addressed (rotated), as shown in FIG. 2. Once the particles are rotated, they stay in that position until an opposite field is applied. This bistable operation requires no electrical power to maintain an image. Another patent, U.S. Pat. No. 5,739,801, disclosed a multithreshold addressable twisting ball display. In this type of display, the electro-optic material 37 is the bichromal spheres and any medium they may reside in to lower their friction in order to rotate.
Most electro-optic displays have problems addressing the display. Since most of the electro-optic materials do not have a voltage threshold, displays fabricated with the materials have to be individually addressed. Some of the liquid crystal materials use an active transistor back plane to address the displays, but these type of displays are presently limited in size due to the complicated manufacturing process. Transmissive displays using liquid crystal materials and a plasma addressed back plane have been demonstrated, for example in U.S. Pat. No. 4,896,149, as shown in FIG. 3. Displays fabricated using the plasma addressed back plane, shown in FIG. 3, are limited in size due to availability of the thin microsheet 33. One potential solution for producing large size displays is to use tubes 27 to create the plasma cells 35, as shown in FIG. 4. Using tubes 27 to create a plasma cell 35 was first disclosed in U.S. Pat. No. 3,964,050, and using fibers 17 with wire electrodes 31 to create the column driving plane in a transmissive plasma addressed liquid crystal display was disclosed in U.S. Pat. No. 5,984,747.
The inventor of the present invention has patents and applications directed to fiber-based displays, including U.S. Pat. No. 6,414,433 entitled “PLASMA DISPLAYS CONTAINING FIBERS”, U.S. Pat. No. 6,771,234 entitled “MEDIUM AND LARGE PIXEL MULTIPLE STRAND ARRAY STRUCTURE PLASMA DISPLAY”, U.S. Pat. No. 6,459,200 entitled “REFLECTIVE ELECTRO-OPTIC FIBER-BASED DISPLAYS”, U.S. Pat. No. 6,611,100 entitled “REFLECTIVE ELECTRO-OPTIC FIBER-BASED DISPLAYS WITH BARRIERS”, U.S. Pat. No. 6,507,146, entitled “FIBER-BASED FIELD EMISSION DISPLAY”, issued Jan. 14, 2003, U.S. Pat. No. 6,452,332 entitled “FIBER-BASED PLASMA ADDRESSED LIQUID CRYSTAL DISPLAY” and U.S. patent application Ser. No. 09/517,353, entitled “FIBER-BASED DISPLAYS CONTAINING LENSES AND METHODS OF MAKING SAME”, filed Mar. 2, 2000. The aforementioned patents and applications are hereby incorporated herein by reference.
There is a need in the art for a display with a conductive surface layer connected to a wire within a fiber.